xref: /openbmc/qemu/hw/misc/sbsa_ec.c (revision a6caeee8)
1 /*
2  * ARM SBSA Reference Platform Embedded Controller
3  *
4  * A device to allow PSCI running in the secure side of sbsa-ref machine
5  * to communicate platform power states to qemu.
6  *
7  * Copyright (c) 2020 Nuvia Inc
8  * Written by Graeme Gregory <graeme@nuviainc.com>
9  *
10  * SPDX-License-Identifier: GPL-2.0-or-later
11  */
12 
13 #include "qemu/osdep.h"
14 #include "qemu/log.h"
15 #include "hw/sysbus.h"
16 #include "sysemu/runstate.h"
17 
18 typedef struct {
19     SysBusDevice parent_obj;
20     MemoryRegion iomem;
21 } SECUREECState;
22 
23 #define TYPE_SBSA_EC      "sbsa-ec"
24 #define SECURE_EC(obj) OBJECT_CHECK(SECUREECState, (obj), TYPE_SBSA_EC)
25 
26 enum sbsa_ec_powerstates {
27     SBSA_EC_CMD_POWEROFF = 0x01,
28     SBSA_EC_CMD_REBOOT = 0x02,
29 };
30 
31 static uint64_t sbsa_ec_read(void *opaque, hwaddr offset, unsigned size)
32 {
33     /* No use for this currently */
34     qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: no readable registers");
35     return 0;
36 }
37 
38 static void sbsa_ec_write(void *opaque, hwaddr offset,
39                      uint64_t value, unsigned size)
40 {
41     if (offset == 0) { /* PSCI machine power command register */
42         switch (value) {
43         case SBSA_EC_CMD_POWEROFF:
44             qemu_system_shutdown_request(SHUTDOWN_CAUSE_GUEST_SHUTDOWN);
45             break;
46         case SBSA_EC_CMD_REBOOT:
47             qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
48             break;
49         default:
50             qemu_log_mask(LOG_GUEST_ERROR,
51                           "sbsa-ec: unknown power command");
52         }
53     } else {
54         qemu_log_mask(LOG_GUEST_ERROR, "sbsa-ec: unknown EC register");
55     }
56 }
57 
58 static const MemoryRegionOps sbsa_ec_ops = {
59     .read = sbsa_ec_read,
60     .write = sbsa_ec_write,
61     .endianness = DEVICE_NATIVE_ENDIAN,
62     .valid.min_access_size = 4,
63     .valid.max_access_size = 4,
64 };
65 
66 static void sbsa_ec_init(Object *obj)
67 {
68     SECUREECState *s = SECURE_EC(obj);
69     SysBusDevice *dev = SYS_BUS_DEVICE(obj);
70 
71     memory_region_init_io(&s->iomem, obj, &sbsa_ec_ops, s, "sbsa-ec",
72                           0x1000);
73     sysbus_init_mmio(dev, &s->iomem);
74 }
75 
76 static void sbsa_ec_class_init(ObjectClass *klass, void *data)
77 {
78     DeviceClass *dc = DEVICE_CLASS(klass);
79 
80     /* No vmstate or reset required: device has no internal state */
81     dc->user_creatable = false;
82 }
83 
84 static const TypeInfo sbsa_ec_info = {
85     .name          = TYPE_SBSA_EC,
86     .parent        = TYPE_SYS_BUS_DEVICE,
87     .instance_size = sizeof(SECUREECState),
88     .instance_init = sbsa_ec_init,
89     .class_init    = sbsa_ec_class_init,
90 };
91 
92 static void sbsa_ec_register_type(void)
93 {
94     type_register_static(&sbsa_ec_info);
95 }
96 
97 type_init(sbsa_ec_register_type);
98